is a major highway on the island of Honshà « in Japan. It connects Chà «à Â, Tokyo in the Kantà  region with the city of Osaka, Osaka Prefecture in the Kansai region, passing through the Chà «bu region en route. It follows the old Tà Âkaidà  westward from Tokyo to Kyoto, and the old Kyo Kaidà  from there to Osaka. Between Tokyo and Aichi Prefecture it parallels the Tomei Expressway; from there to Mie Prefecture, the Higashi-Meihan Expressway, and from Shiga Prefecture to Osaka, the Meishin Expressway. It has a total length of . At its eastern terminus in Nihonbashi, Chà «à Â, Tokyo, it meets National Routes 4, 6, 14, 15, 17, and 20. At its western terminus in Umeda, Kita-ku, Osaka, it links with Routes 2, 25, 26 and other highways.
National Route 1 links Tokyo to the important prefectural capitals of Yokohama (Kanagawa Prefecture), Shizuoka, Nagoya (Aichi Prefecture), Otsu (Shiga Prefecture), Kyoto, and Osaka. It is the modern incarnation of the pre-modern Tà Âkaidà Â.
The main line of National Route 1 has a length of . When bypasses signed as National Route 1 are included, its total distance increases to . Out of all of the national highways in Japan, it is the second longest land-based route after National Route 4, though National Route 58 is the longest route when seabound routes are factored in.
The highway's origin and eastern terminus lie at Nihonbashi in Tokyo's Chà «à  ward. At Nihonbashi it meets national routes 4, 6, 14, 15, 17, and 20. The highway passes through the cities of Kawasaki, Yokohama, Odawara, Numazu, Shizuoka, Hamamatsu, Nagoya, Yokkaichi, à Âtsu, and Kyoto. Its endpoint and western terminus lie in the Umeda district of Osaka's Kita ward. In Umeda, it has a junction with national routes 2, 26, 163, 165, 25, and 176.
National Route 1 was preceded by the Tà Âkaidà  between Tokyo and Kyoto and the old Kyo Kaidà  from Kyoto to Osaka. The road's construction was ordered by the first shà Âgun of the Edo period, Tokugawa Ieyasu. It served to link the old capital of Japan, Kyoto, to Tokugawa's new capital, Edo. The Tà Âkaidà Â's post stations, known in Japanese as shukuba, were captured by the printmaker Utagawa Hiroshige in his ukiyo-e prints, The Fifty-three Stations of the Tà Âkaidà Â.
In 1919, the first Road Act was passed, establishing a highway also called National Route 1 between Tokyo and the city of Shingà « in Wakayama Prefecture partially along the current route. On 4 December 1952 the route was designated by the Cabinet of Japan as Primary National Highway 1 between Tokyo and Osaka, establishing the highway almost entirely along its current routing. On 1 April 1965 the route was redesignated as General National Route 1.
All junctions listed are at-grade intersections unless noted otherwise.